• 한국도로학회논문집
• /
• 제20권2호
• /
• pp.9-17
• /
• 2018

PURPOSES : The frequency and severity of natural disasters such as torrential rain or typhoons have become increasingly significant worldwide. Events such as summer typhoons and localized torrential downpour can cause severe damages to a residential area and road networks, resulting in serious harm to the daily lives of people, especially in rural areas by isolating residents from road networks. An immediate and emergency repair technology for the collapsed road networks is urgently needed. This study introduces a new technology to repair road bases or slopes. METHODS : The development of new technology for emergency and permanent repair consists of first, packing of cement paste-coated gravel, second, combining appropriate equipment, and third, conducting a field applicability test. In this research, the compressive strength of cement pastecoated gravel, gravel-netting concrete properties, and packing efficiency were determined, and a full scale field mock-up test was carried out. RESULTS : The compressive strength of the cement paste-coated gravel concrete satisfied the required limit for road base of 5 MPa after 7 days. With appropriate netting materials and packing size, gravel-netting concrete was successful up to a slope of 1:1.5. The full scale field mock-up test showed efficiency in the field and penetration resistance performance. CONCLUSIONS : The new technology of emergency and permanent repair for damaged road bases and slopes, introduced in this study, showed satisfactory performance. The technology is expected to be applied in the field when construction procedures and quality specifications are made.

• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 1997년도 추계학술대회 논문집
• /
• pp.265-268
• /
• 1997

In the recent day, fatigue life prediction techniques play a major role in the design of components in the ground vehicle industry. Full scale durability testing in the laboratory is an essential of any fatigue life evaluation of components or structures of the automotwe vehicle. Component testing is part~cularly important in today's highly competitive industries where the design to reduce weight and production costs must be balanced with the necessity to avoid expensive service failure. Generally, multi-axial road simulator is used to carry out the fatigue test and the vibration test. In this paper, the algorithm and software to realize the real road profile are developed. The validity of the software are verified by applying the belgian road, the city road, the highway, and the gravel road. The results of the above experiment show that the real road profiles are realized well after loth iteration.

• 한국자동차공학회논문집
• /
• 제10권5호
• /
• pp.190-198
• /
• 2002

Full scale durability test in the laboratory is an essential of any fatigue life evaluation of components or structures of the automotive vehicle. Component testing is particularly important in today's highly competitive industries where the design to reduce weight and production costs must be balanced with the necessity to avoid expensive service failure. Generally, hydraulic road simulator is used to carry out the fatigue test and the vibration test. In this paper, the algorithm and software to realize the real road profile are developed. The operation software for simultaneously controlled multi-axial road simulator is developed and the input and output data are displayed window based PC controller in the real time. Futhermore, the software to generate the real road profile are developed. The validity of the software are verified by applying the belgian road, the city road, the highway, and the gravel road. The results of the above experiment show that the real road profiles are realized well after 10th iteration.

• 한국도로학회논문집
• /
• 제20권1호
• /
• pp.9-18
• /
• 2018

PURPOSES : In this research, the initiation and development of corrugation on a gravel road with certain wheel and boundary conditions were evaluated using a coupled discrete-element method (DEM) with multibody dynamics (MBD). METHODS : In this study, 665,534 particles with a 4-mm diameter were generated and compacted to build a circular roadbed track, with a depth and width of 42 mm and 50 mm, respectively. A single wheel with a 100-mm diameter, 40-mm width, and 0.157-kg mass was considered for the track. The single wheel was set to run slowly on the track with a speed of 2.5 rad/s so that the corrugation was gradually initiated and developed without losing contact between the wheel and the roadbed. Then, the shape of the track surface was monitored, and the movement of the particles in the roadbed was tracked at certain wheel-pass numbers to evaluate the overall corrugation initiation and development mechanism. RESULTS : Two types of corrugation, long wave-length and short wave-length, were observed in the circular track. It seems that the long wave-length corrugation was developed by the longitudinal movement of surface particles in the entire track, while the short wave-length corrugation was developed by shear deformation in a local section. Properties such as particle coefficients, track bulk density, and wheel mass, have significant effects on the initiation and development of long-wave corrugation. CONCLUSIONS : It was concluded that the coupled numerical method applied in this research could be effectively used to simulate the corrugation of a gravel road and to understand the mechanism that initiates and develops corrugation. To derive a comprehensive conclusion for the corrugation development under various conditions, the driver's acceleration and deceleration with various particle gradations and wheel-configuration models should be considered in the simulation.

• 한국지반환경공학회 논문집
• /
• 제6권3호
• /
• pp.17-23
• /
• 2005

매년 콘크리트구조물의 해체로 폐콘크리트는 증가하고 있으며, 해체되어 발생한 폐콘크리트 덩어리를 순환골재로 만들어 도로재료로 재활용하고 있다. 그러나 폐콘크리트의 공학적 환경적 안정성에 대한 연구가 미흡하여 재활용율이 낮다. 본 논문은 이러한 문제점을 해결하기 위하여 일반쇄석과 순환골재의 비교 분석을 실시하였다. 순환골재의 공학적 특성 시험인 액성한계, 소성지수, CBR, 모래당량, 마모시험과 환경적 특성시험인 pH, 컬럼용출 시험을 실시하였다. 실험결과, 순환골재의 공학적 특성은 노체, 노상, 보조기층에 적합한 것으로 나타났으나, 기층재료로는 부적합한 것으로 나타났다. 순환골재의 환경적 특성으로 pH, 장기용출시험결과, pH는 11정도로 나타났으며, 용출시험결과는 폐기물관리법의 환경기준치 이내로 비교적 안전한 것으로 나타났다. 따라서, 순환골재를 도로재료로 활용하더라도 공학적 환경적으로 안전한 것으로 판단된다.

• 한국토양비료학회지
• /
• 제47권2호
• /
• pp.113-119
• /
• 2014

Arsenic and its compounds which is one of the most toxic elements that can be found naturally on earth in small concentrations are used in the production of pesticides, herbicides, and insecticides. Most arsenic that cannot be mobilized easily when it is immobile is also found in conjunction with sulfur in minerals such as arsenopyrite (AsFeS), realgar, orpiment and enargite. In this investigation we observed the leaching of arsenic in soils amended with several levels of gravel size of arsenopyrite collected from a road construction site. Soil and gravel size of arsenopyrite were characterized by chemical and mineralogical analyses. Results of XRF analysis of arsenopyrite indicated that the proportion of arsenate was 0.075% (wt $wt^{-1}$) while the maximum amount of arsenic in soil samples was 251.3 mg $kg^{-1}$. Cumulative amounts of effluent collected from the bottom of the soil column for different mixing rate of the gravel were gradually increased where proportion of the gravel mixed was greater than 70% whereas the effluent was stabilized to the maximum after approximately 45 pore volumes of effluent or greater were collected. The arsenic in the effluent was recovered from the soil columns in which the proportion of arsenopyrite gravel was 60% or greater. The total amount of arsenic recovered as effluent was increased with increasing proportion of gravel in a soil, indicating that the arsenic in the effluent was closely related with gravel fraction of arsenopyrite.

• 한국정밀공학회지
• /
• 제24권7호
• /
• pp.106-111
• /
• 2007

In this paper, the transient brake time was studied on the van type vehicle with accelerometer. Experiments were carried out on the asphalt(new and polished), unpacked road(earth and gravel) and on wet or dry road conditions. The transient brake time is not effected bzy the vehicle speed. The transient brake time is about 0.41$\sim$0.43second on the asphalt road surface and the error range is within 0.1$\sim$0.16second. For the asphalt road condition, the transient brake time is not effected by both new asphalt road surface and the polished asphalt road surface. With compared by dry and wet road surface condition, the transient brake time of wet condition is longer than dry road condition and compared with unpacked road condition and packed road condition, unpacked road condition is shorter than packed road condition. It is considered that the transient brake time is effected by the road surface fraction coefficient. In other words, the transients brake time increases as friction coefficient decreases.

• 한국산림과학회지
• /
• 제89권3호
• /
• pp.397-404
• /
• 2000

임도 옆도랑침식에 영향을 미치는 요인의 평가 및 안정도 판별을 위하여 광릉시험림의 임도를 대상으로 조사를 실시한 결과 침식에 미치는 기여순위는 종단물매, 시설위치, 절토사면경사, 절토사면구성물질, 유하거리, 노면형태, 노면재료, 절토사면피복도, 절토사면길이 순으로 나타났다. 임도 옆도랑침식을 유발하는 요인을 평가하면, 종단물매는 8% 이상, 임도시설위치는 산록(山麓)과 중복(中腹), 절토사면경사는 $50^{\circ}$ 이상, 절토사면토성은 견질토사, 자갈섞인 토사, 호박돌섞인 토사, 유하거리는 80m 이상의 지역에서, 그리고 노면재료는 토사도(土砂道)와 자갈부설도에서, 노면형태의 경우에는 철(凸)형과 직선형, 절토사면 피복도(被覆度)는 피복도가 중(中)이상인 곳에서 임도 옆도랑침식이 발생할 가능성이 높은 것으로 예측(豫測)되었다.

• 한국환경복원기술학회지
• /
• 제7권3호
• /
• pp.14-25
• /
• 2004

The purpose of this study was investigated to the change of vegetation coverage by elapsed years on the cut slope of forest road in Jinju-si. The results obtained could be summarized as follows; The plant coverage on the cut slope of forest road was decreased hastily in first and second year after seeding. The plant coverage on the cut slope of forest road was increased as growth of seed-sprayed from third year. But the plants were began to competition with between sprayed seeds and invaded plants from third to fifth year after seed-spray. The numbers of invading plants were gradually increased as 581 individuals from sixth year after seed-spray. The cut slopes of the forest roads turned to a good site condition for growing of invasion plants. And also the total coverage on cut slope of forest roads by invading of surrounding plants was increased more. It showed that plant invasion on cut-slopes of forest roads would be mostly influenced by surrounding plants. The number of surrounding plants on the cut-slopes of forest roads was 59 species, and the number of invading plants showed 65 species. The invading species were high in order of Boehmeria tricuspis, Oplismens undulatifolius, Miscanthus sinensis var. purpurascens, Erechtites hieracifolia and Artemisia princeps var. Orientalis In the stepwise regression analysis, main factors affecting the coverage of vegetation on the cut-slopes of forest road showed in order of elapsed years, gravel contents(30~50%), middle, sandy loam, sandy clay-loam, soil hardness, aspect(NS), concave(凹) type and gravel contents(15~30%).

• 한국도로학회논문집
• /
• 제17권2호
• /
• pp.63-70
• /
• 2015

PURPOSES: As a part of our research into repair techniques for roads that have collapsed as a result of a natural disaster, this study set out to find the optimum mix proportion for gravels to be used to restore a damaged area. METHODS: This study considered flow and strength-development characteristics. The experimental variables were the W/C ratio, the usage of the admixture, the types of cement, and the quantity of fine aggregate over three different experimental stages. The compressive strength was measured at 12 hours, one day, three days, and seven days. RESULTS : The flow varied with the amount of fine aggregate and the use of a high-range water-reducing (HRWR) admixture. The compressive strength also varied with respect to the type of cement and the W/C ratios. The strength satisfied the expected requirement of 21 MPa after one day, provided the mix proportion was appropriate. CONCLUSIONS: A gravel-filling high-flow cement-based mortar exhibited strength and consistency with a W/C ratio in the range of 0.40 to 0.45, assuming the use of HRWR at 0.5 to 0.7% and a fine aggregate/cement ratio of 1.0 to 1.5.